The present disclosure relates to a wiper unit, particularly to an ice wiper for hydraulic working apparatuses, for protecting a secondary side against environ-mental influences occurring at a primary side, particularly for protecting guide arrangements and/or sealing arrangements, comprising a retaining ring, a primary wiper and a secondary wiper. The disclosure further relates to a hydraulic working apparatus, particularly a hydraulic cylinder, comprising such a wiper unit.
Wiper units (also: wiper) of a general kind which may be also referred to as dirt wipers, ice wipers and such like, are known in the art and used for a multitude of cylinder-piston-arrangements which are exposed to exterior environmental influences. Conventional wipers may be for instance used for vehicle shock absorbers and similar hydraulic and/or pneumatic devices, wherein for instance a piston rod is moved relative to a housing. This frequently involves that parts of the piston rod come into direct contact with the environment and are exposed to dirt, icing, humidity and such like, for instance. It is known in the art to implement wipers so as to protect sealing elements, bearing elements and/or guide elements arranged behind the wipers against at least coarse dirt and such like.
Wipers of a general kind are for instance known from WO 2007/101414 A1, DE 10 2006 002 347 A1 and U.S. 2005 006 7242 A1.
However, there are further applications known where conventional wiper units reach limits of performance and may no longer provide a sufficient cleaning function and/or protecting function. This may be for instance the case with building machines. A further, extremely critical case of application may be present with hydraulic machinery and/or hydraulic working apparatuses which are used on the sea (offshore). Such facilities are exposed to humidity, a huge salt content (salinity) and/or extreme temperatures. By way of example, a considerable formation of ice may be frequently observed at piston rods at offshore facilities.